Social security income is not taxable if it was the only income a person received in 2014, according to the Social Security Administration. Individuals who earned a sustainable income through other sources outside of Social Security must pay taxes on a portion of their SSA benefits.
Other sustainable wages include money from investments, a part-time job, rental income or any other money earned from the selling of goods or services. If individuals file taxes separately from their spouses and their income falls between $25,000 and $35,000, the IRS may require them to pay taxes on 50 percent of their Social Security income. The income for a joint return is $35,000 to $45,000, which requires individuals to pay income taxes on 85 percent of their Social Security benefits, states the Social Security Administration.